I come to the city of Wrocław, the former Breslau, by train. Until Pardubice, the train is modern and certain, spacious and sleek. In the arms of this doleful efficiency, I sleep. From Pardubice, we step through a looking glass, and the fabric and character of the journey are wholly transformed. The wagons, now subdivided into dark and cozy cabins, no longer slice smoothly through the cold morning air, they jostle and shake gently, a half-hearted rebellion against friction and gravity. A train of infinite patience, it pauses to stop at every hamlet, no matter how small, and heeds the whim of any local dweller to travel, from one whistle-stop to the next, on this particular day.

At each grade level crossing, we pass a semaphore, our motion smearing the sounds of the dinging bells, like a foley cue from an old spy film. It begins high on the musical scale and then smoothly sweeps downward, simultaneously rising and falling in loudness, a small seance to summon the spirit of Christian Doppler. It was he who, in 1842 at the Prague Polytechnic, proposed an explanation to account for the audible change in pitch of a sound that is in motion relative to a perceiver. Doppler extrapolated his principle to all forms of undulating energy, so it is due to him that we can divine the relative velocities of the stars, a fundamental tool for knowing where we are among all things that exist. This was no small contribution.

Crossing the border into Poland, the stops become less frequent, the scenery a bit flatter and more docile, a green land, fertilized with the blood of nations, and their ashes. Sometimes, this pastorale is broken by the sooty apparition of a vast complex of rusting equipment and fuming smokestacks, sitting among pits and piles of disturbed earth. The sky shimmers with surprising sparks, as small birds with wings black on top, but white undersides, flap their way over the fields in tight, elastically bound clusters, glinting like diamond dust rendered in an animated gif from a Japanese web site.

The postwar past of Wrocław is a tragic saga of mass migrations, people forced in large numbers to leave their homes, only to be replaced by waves of newcomers who themselves were driven out of their abodes. Architectural forms devised to suit the needs of the previous denizens at times found an odd fit with the recently arrived. This has left this richly layered city fragmented, but not broken. Wrocław spreads out in all directions from a center that is fractured by some dozen islands in the river Odra. These islets sit firmly in the brown water among a lacework of bridges, like so many foundering barges heaped up with earth and crowned with traces of a past cultural, religious and industrial. If the dazzle of the early morning sun blinds and obscures, its sieve also showers light on the diaphanous scrims of vapor that hang between us and Baroque façades, bell towers, blocks of flats, and chimneys that shy behind cold curtains of mist. Ducks glide, drawing wakes, recalling the resonances of sound waves made visible. Black crows in vests of gray, de-tuned trumpets squawking with the compressive thrust of a dog’s squeak toy, play games in mid-air, at times floating down to scrabble over bits of bread and other things interesting to crows. An autumn tree, its few remaining leaves rocking back and forth in the soft breeze, a glint of intermittent gold, a dazzle, a rustling of their almost silent tissues.

The trams here squeal like stuck pigs as they carefully round tight corners, blue painted boxes with large windows on steel wheels, filled with lego-land passengers moving on to the next moment of their lives. Old buildings are festooned with a blight of bubbling masonry, crumbling plaster façades, and a cast of thousands in the form of molded plaster busts crouch in dim alcoves, niches for effigies of the once admired, but now obscure.

We come across a meridian line on the sidewalk ceremoniously marked by a bronze plaque. The building it points to, the Uniwersytet Wrocławski, houses a museum crested with an astronomical observatory. Ascending the steps, we find a high opening in the wall that admits a single streak of sunlight, projecting onto the floor and forming a bright line that marks the meridian (in the modern exhibit, this line is “enhanced” with a string of LEDs). If Doppler’s shift is dynamic and ever varying, a dance of sound and movement, this line is steady and sure. It follows the edge of Euclid’s ruler, and fixes our location in time with a certainty that seems God-like.